Conventionally, an image forming apparatus (for example, a multifunction peripheral or MFP) includes a transfer belt and an image process unit including a photosensitive drum. The image process unit including the photosensitive drum is a consumable item, that the user replaces as needed. In order to prevent the transfer belt from being damaged at the time of replacing the image process unit, it is necessary to separate the transfer belt from the photosensitive drum. In order to bring the transfer belt into a non-contact state with respect to the photosensitive drum, the transfer belt is moved by a position switching roller arranged inside the transfer belt.
However, when the transfer belt is deteriorated and stretched by use over time, a sufficient tension cannot be applied to the transfer belt. Therefore, it becomes difficult to sufficiently separate the transfer belt from the photosensitive drum. As a result, a part of the image process unit is rubbed or hooked to the transfer belt to damage the transfer belt when the image process unit is replaced.